An important landmark has been reached in the construction of Crossrail, London's £14.8bn rail programme. The tunnelling of 21km of twin-bore tunnels dug beneath the capital is well underway and the project is now at the half way stage assuming things run to plan. The first tunnel was completed in November 2013.
The scale of the project is epic - one of a number of infrastructure projects that are underway or in the planning stage in the UK. the importance of infrastructure investment is often debated by economists. They can affect both aggregate demand and aggregate supply and have wider effects on a nation's competitiveness.
